Spotting

Hey! This is from an extremely nervous first time mum-to-be! I done a pregnancy test which said I was 2-3 weeks, a tracker I got for my phone says 5 weeks. Last night I started experiencing cramps, nothing severe just enough for me to notice it and become terrified! I also started noticing brown discharge, this is similar to what happens to me as my period is about to begin except there is more of it than usual! Just looking for some reassurance from other mums-to-be that this is common! Thanks!!!